That, at any rate, was my view at the time: editors, it seemed, would have to be much more cautious in future over the photographs and details they published about individuals, even when the basic facts could be freely reported.

But not everyone agreed with this reading of the law lords' judgments. On the day they were handed down, one solicitor at a leading media firm insisted that "this is not the bad news for press freedom some commentators suggest it is". The "overall result," she added, was one to be "welcomed by the media".

Can this be right? Naomi Campbell, of course, persuaded the law lords that the Mirror should not have published details of the therapy she was receiving for drug addiction or pictures of her leaving a meeting of Narcotics Anonymous. Tonight, one of the leading judges in the field of privacy and defamation will give his own view of the first post-Human-Rights-Act "privacy" claim to reach our highest court.

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Sir Charles Gray - who, as Mr Justice Gray, is currently trying the "Indecent Proposal" slander case in the High Court - believes that "the alarm felt by some sections of the media is understandable".

"Editors will have to think long and hard about kiss-and-tell stories," he says in the annual Margaret Howard Memorial Lecture, to be delivered in Oxford. "Photographs will be a particular problem."

When we meet to discuss his remarks, he reminds me that kiss-and-tell stories are "meat and drink" to the tabloids. But should the courts have stepped in to protect privacy where Parliament has deliberately chosen not to tread? "This is very delicate territory," he replies.

The Campbell case, he says, turned on a very narrow point: the model accepted that the Mirror could report the fact of her drug addiction and treatment, but challenged the detail and photographs. In his view newspapers have to be allowed the journalistic latitude or "margin of editorial judgment" that the Court of Appeal and a minority of the law lords supported. It was unfortunate, therefore, that this was the one "privacy" case that went to the House of Lords.

"The trouble with privacy is that it is always the celebrities and the people in the public eye who sue. But the people who matter are the families who are plagued by television news cameras after some dreadful tragedy."

They may find Miss Campbell riding to their rescue. Sir Charles believes that the judgment has, in effect, created a law of privacy for the first time. Judges have taken the old-established law of confidence, which was founded on a prior relationship between two parties, and transformed it into a new law preventing what Lord Nicholls called "the misuse of private information".

Making new laws from old in this way has been called the "genius of the common law", says Sir Charles. "The law lords have realised that there is a problem which is not being addressed properly by the existing causes of action, and they have exercised quite radical re-moulding to address what they perceive to be a problem."

And what difference will this new privacy law make? Sir Charles gives me the example of a police officer who does not wish details of his sexual orientation to be made public. Though he does not say so, it is clear that the judge has in mind the example of Brian Paddick, the senior Scotland Yard officer who took action against the Mail on Sunday for breach of confidence.

The case was settled last December. If it is not in the public interest for an individual's sexuality to be revealed, Sir Charles believes that the courts will now protect his privacy. But exactly what the law regards as being in the public interest has yet to be defined.

Sir Charles is concerned about balancing the increased rights of privacy with freedom of expression - the theme of his lecture tonight. "However much one deplores the irresponsibility of large sections of the media, the temptation to curb press freedom must be resisted," he says.

"Freedom of expression is a right that is well worth preserving and protecting. Free speech, whether in the media or elsewhere, is valuable because it enables other important rights to be defended and abuses of power to be exposed."

On the other hand, he believes that the laws on libel and slander are much less of a threat to freedom of expression than they were even a decade ago.

One reason is that the days of huge damages came to an end in 1995, when the Court of Appeal ruled on a case brought by Elton John against the Sunday Mirror. Sir Elton's award of £350,000 was slashed to £75,000, and the effective ceiling is now £200,000: small change compared with the record £1.5 million awarded - though never paid - to the late Lord Aldington in 1989.

Sir Charles suggests that the pendulum may have swung too far in the direction of the media. "Awards, nowadays, are not high enough to make an editor think twice before publishing," he says, arguing that levels should be increased.

Costs are another matter, though. Until very recently, claimants suing under no-win, no-fee arrangements - conditional fee agreements, or CFAs - could hold defendants to ransom. "The empowerment of CFA-financed libel claimants" - who may have weak claims - "poses a real threat to freedom of expression," Sir Charles says.

In a CFA-funded libel case brought against The Sunday Telegraph by a man suspected of involvement in terror-related activities, the Court of Appeal ruled last week that costs could be capped. "Time will tell whether this will solve the problem," Sir Charles says.

Another safeguard for free expression is what lawyers call Reynolds privilege, which protects reporters even if they cannot prove that their reports were true. This stems from a ruling by the law lords in 1999 on a case brought against the Sunday Times by a former prime minister of Ireland - and it gives journalists a defence against libel, provided they have behaved "responsibly".

As Sir Charles says, "the defence of privilege is now available in many cases where it would not previously have been". There are also signs that the media will be able to place greater reliance on the defence of "fair comment" - even if commentators have agendas of their own.

So, how well have the courts struck the balance between free speech and other interests, such as respect for privacy and reputation? Sir Charles believes it is just about right at the moment. But he adds: "One needs to be vigilant about threats to freedom of expression, from whatever quarter they may come".

Sir Charles Gray will be speaking at 5.45pm tonight at the Law Faculty, St Cross Road, Oxford. The event will be chaired by Michael Beloff, QC, and all are welcome.